O.K. time for stupid questions;

based on the photos in the above link, the prop mount is still using a single bolt attachment. I have seen a number of the BME 102 at our club field that use this same method. It seems that the guys flying these have do a lot of checking/re-tightening compared to the six bolt mounts on the DA or ZDZ. SOOO

Is this really the best prop mount system?
Is it safe on an engine of this size?

Just curious, since I will be in the market next spring.